WordPress security changelog
MEDIUM CVE-2026-9838 Deferred

ICS Calendar: Cross-site scripting

ICS Calendar is affected by cross-site scripting. The vulnerable path is reachable without authentication. Injected script can execute in the affected site's origin when the vulnerable output is viewed. The published affected range is <= 12.0.9.

CVE / CNA score 6.1 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
ICS Calendar
Plugin slug
ics-calendar
Affected
<= 12.0.9
Safe version
> 12.0.9
Published
Jul 10, 2026
Weakness
CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

This CVE was published Jul 10, 2026 and is one of 3 known issues for this plugin.

What to do

Update, patch or deactivate.

Update ICS Calendar to a release after 12.0.9, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical description

The ICS Calendar plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'htmltagtitle' parameter in all versions up to, and including, 12.0.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. The vulnerability is reachable via the unauthenticated wp_ajax_nopriv_r34ics_ajax AJAX action, which accepts attacker-controlled js_args values merged over stored shortcode configuration without nonce verification, allowing the htmltagtitle key to bypass the normal shortcode allowlist check.

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

Primary and upstream sources